1. Field of the Invention
The present invention relates to a packaging film to allow an article to be wrapped in a packaging film capable of sealing by heating both ends thereof, and, in particular, relates to a packaging film to allow itself to be removed easily from the packaged article.
2. Description of the Related Art
Generally, various goods are sold being wrapped in a packaging film such as cellophane.
FIGS. 1(A) and 1(B) are perspective view for explaining an ordinary packaging structure using a packaging film in a prior art.
Referring to FIGS. 1(A) and 1(B), a description is given of an ordinary packaging film structure in the prior art, taking an example in which an article 1 to be packaged, a tape cassette accommodated in a protection case, is wrapped up in a packaging film 2 made of, for instance, cellophane, polypropylene or polyethylene telephtalate.
At first, as shown in FIG. 1(A), after a tear tape 3 has been adhered on an inside of the packaging film 2 along a wrapping direction or a lateral direction of the packaging film 2, the packaging film 2 wraps the article 1 in a cylindrical state. An overlapped portion of both ends of the packaging film 2 is connected together by heating. A pair of nicks (or one notch) 4 are preliminary provided nearby one side of the tear tape 3 at a distal end of the packaging film 2 located on an upper side of the overlapped portion 5 to allow the tear tape 3 to be removed readily.
Next, as shown in FIGS. 1(A) and 1(B), free edges 6A and 6B arranged in a longitudinal direction of the packaging film 2, are folded inside together and are connected by welding. Thus, the article 1 is packaged by the packaging film 2.
Upon removing the packaging film 2 from the article 1 packaged, the tear tape nearby the nicks 4 unpacks the article 1 by separating the packaging film 2 as pulled up along a circumference of the article 1. Thus, the article 1 is taken out therefrom.
In the prior art, there are also proposed other film packaging structures requiring no tear tape.
A description is given an example of them in reference to FIGS. 2(A) and 2(B).
FIGS. 2(A) and 2(B) are perspective views for explaining another packaging structure using a packaging film having no tear tape in the prior art.
As shown in FIGS. 2(A) and 2(B), a non-bonded portion 7 is provided to the overlapped portion 5 of the packaging film 2, and a nick 4 is provided nearby the non-bonded portion 7. The overlapping portion 5 except for the non-bonded portion 7 and the free edges 6A and 6B in the longitudinal direction are bonded by heating in the same manner as mentioned in the foregoing.
The packaging film 2 is removed by tearing from the non-bonded portion 7 in cooperation with the nick 4. Then, the article 1 is taken out therefrom.
In the packaging structure shown in FIGS. 1(A) and 1(B), it requires an exclusive equipment for providing the tear tape 3 on the inside face of the packaging film 2. This inevitably invites an increase of the production facility cost.
Further, when employing a heat-shrinking plastic film as the packaging film 2, wrinkles may occur in the portion on which the tear tape is adhered, resulting from the difference of heat shrinkage between the packaging film 2 and the tear tape 3. This causes a degradation of appearance of the article 1 packaged.
Furthermore, when the tear tape 3 is pulled to tear the packaging film 2, only the tear tape may be removed from the packaging film 2 leaving the packaging film 2 as is. This results in being difficult to remove the packaging film 2 from the article 1.
FIGS. 3(A) and 3(B) are perspective views for explaining problems occurring in the packaging film structure in the prior art.
As shown in FIG. 3(A), when the packaging film 2 is separated into two parts, i.e., one portion having a smaller area 2A and another portion having a larger area 2B, by removing the tear tape 8, it is likely that the portion 2A having the smaller area can be readily removed therefrom but the other portion 2B having the larger area remains thereon. This causes a problem that the other portion 2B remaining on the article 1 is difficult to be removed therefrom.
As disclosed in Japanese Patent Laid Open Publication, H3-29766/1991, there is also proposed a packaging film structure requiring no tear tape, wherein a packaging film has an orientation in a tearing direction of the packaging film to allow the packaging film to be torn. In this case, the packaging film is also separated into two portions, i.e., one portion having a smaller area and another portion having a larger area. This causes the same problem that the other portion having a larger area remains thereon and is difficult to be removed therefrom, as mentioned in the foregoing.
In the packaging film structure having no tear tape 3 shown in FIGS. 2(A) and 2(B), there is a problem that a portion nearby the nick 4 curls upward in the heat sealing process or heat shrinking process as shown in FIG. 3(B). This causes a degradation of appearance of the article 1.